This invention relates generally to a composter, and more particularly to a composter for rapidly, economically and naturally composting organic waste.
Waste can be defined as post-consumer materials with positive economic value removed and negative value added. For instance, "garbage," in its usual sense, carries a cost by occupying space valuable for other purposes thereby requiring transport to and disposal at a waste collection site. Organic materials such as food waste also incur health and sanitation penalties in the form of odor production, attraction of vermin, and the potential for harboring pathogens. When mixed with the rest of the waste stream, the putrescible organic portion makes carting and disposal of the entire solid waste stream substantially more difficult and unpleasant.
Recycling waste materials restores positive economic value and removes negative value. Recycling, when it has been able to work in the face of market mechanisms, recovers materials from the waste stream and feeds them back into the supply stream for some industry or service, thus bringing the material back to the consumer and "closing the loop" by connecting resources, production and consumption in much the same way that closed ecological systems work.
Composting, as a form of recycling, can serve this recovery function for the organic portion of the waste stream which may range from 10% to 30% of the total waste stream. The potential for composting as a solution to the organic solid waste crisis is highlighted by the facts that more than one thousand municipal yard waste compost facilities presently operate in the United States, and that 8% to 20% of American households currently compost in their backyards. Thus, the opportunity and motivation to compost exists.
In the past, most composting has been accomplished at one of two vastly different scales. At the small scale, individuals have manually composted in their backyards or gardens using a simple pitchfork and a compost bin to agitate the waste material to assist the composting process. This process is inexpensive but labor intensive, slow and unpleasant due to the odor of the organic waste. At the very large scale, automatic equipment has been used for moving and mixing organic waste material through a silo, rotating drum or tunnel reactor at high speeds and high RPM. While the labor cost per unit of compost material is low, the equipment is large and very expensive, thus being inappropriate for smaller scale users. Moreover, even with powerful mixing machinery, the rate of composting is still fairly slow, requiring approximately sixty to ninety days to complete. The use of high power, high r.p.m., large surface area blade and auger mixing systems can retard the rate of composting by compacting the compost mixture, resulting in reduced surface area-to-volume ratios and insufficient air circulation throughout the compost mixture required for rapid composting. For instance, because the surface compaction of the organic mixture is roughly proportional to the surface area of the mixing blade, large blades can cause overly large chunks of waste material. In addition, when the force per area imparted by the rapidly turning mixing blade to the compost mixture is greater than the compressive strength of the compost mixture itself, the compost mixture is compressed into clumps. Moreover, any lateral or downward resultant forces imparted by the blade on the mixture will compact the adjacent compost mixture, and any "chunks" of material which are dropped or fall from heights greater than two to three feet will compact the mixture below on impact.
Accordingly, it is desired to provide a small to medium scale composting system which completes the composting process rapidly, yields a substantially odorless product, foregoes the use or production of materials which may be harmful to the environment, and is simple and inexpensive to install and operate.